Navigation device &amp; method

ABSTRACT

This invention relates to a navigation device ( 200 ) comprising a processor ( 210 ); and a store ( 230 ) containing map data, wherein the map data comprises a temporally-variable feature and the processor ( 210 ) is arranged, in a route planning process, to determine a status of the temporally-variable feature according to temporal information

FIELD OF THE INVENTION

This invention relates to navigation devices, systems and to methods forproviding navigation information. Illustrative embodiments of theinvention relate to portable navigation devices (so-called PNDs), inparticular PNDs that include Global Positioning System (GPS) signalreception and processing functionality. Other embodiments relate, moregenerally, to any type of processing device that is configured toexecute navigation software so as to provide route planning, andpreferably also navigation, functionality.

BACKGROUND TO THE INVENTION

Portable navigation devices (PNDs) that include GPS (Global PositioningSystem) signal reception and processing functionality are well known andare widely employed as in-car or other vehicle navigation systems.

In general terms, a modern PNDs comprises a processor, memory (at leastone of volatile and non-volatile, and commonly both), and map datastored within said memory. The processor and memory cooperate to providean execution environment in which a software operating system may beestablished, and additionally it is commonplace for one or moreadditional software programs to be provided to enable the functionalityof the PND to be controlled, and to provide various other functions.

Typically these devices further comprise one or more input interfacesthat allow a user to interact with and control the device, and one ormore output interfaces by means of which information may be relayed tothe user. Illustrative examples of output interfaces include a visualdisplay and a speaker for audible output. Illustrative examples of inputinterfaces include one or more physical buttons to control on/offoperation or other features of the device (which buttons need notnecessarily be on the device itself but could be on a steering wheel ifthe device is built into a vehicle), and a microphone for detecting userspeech. In a particularly preferred arrangement the output interfacedisplay may be configured as a touch sensitive display (by means of atouch sensitive overlay or otherwise) to additionally provide an inputinterface by means of which a user can operate the device by touch.

Devices of this type will also often include one or more physicalconnector interfaces by means of which power and optionally data signalscan be transmitted to and received from the device, and optionally oneor more wireless transmitters/receivers to allow communication overcellular telecommunications and other signal and data networks, forexample Wi-Fi, Wi-Max GSM and the like.

PND devices of this type also include a GPS antenna by means of whichsatellite-broadcast signals, including location data, can be receivedand subsequently processed to determine a current location of thedevice.

The PND device may also include electronic gyroscopes and accelerometerswhich produce signals that can be processed to determine the currentangular and linear acceleration, and in turn, and in conjunction withlocation information derived from the GPS signal, velocity and relativedisplacement of the device and thus the vehicle in which it is mounted.Typically such features are most commonly provided in in-vehiclenavigation systems, but may also be provided in PND devices if it isexpedient to do so.

The utility of such PNDs is manifested primarily in their ability todetermine a route between a first location (typically a start or currentlocation) and a second location (typically a destination). Theselocations can be input by a user of the device, by any of a wide varietyof different methods, for example by postcode, street name and housenumber, previously stored “well known” destinations (such as famouslocations, municipal locations (such as sports grounds or swimmingbaths) or other points of interest), and favourite or recently visiteddestinations.

Typically, the PND is enabled by software for computing a “best” or“optimum” route between the start and destination address locations fromthe map data. A “best” or “optimum” route is determined on the basis ofpredetermined criteria and need not necessarily be the fastest orshortest route. The selection of the route along which to guide thedriver can be very sophisticated, and the selected route may take intoaccount existing, predicted and dynamically and/or wirelessly receivedtraffic and road information, historical information about road speeds,and the driver's own preferences for the factors determining road choice(for example the driver may specify that the route should not includemotorways or toll roads).

In addition, the device may continually monitor road and trafficconditions, and offer to or choose to change the route over which theremainder of the journey is to be made due to changed conditions. Realtime traffic monitoring systems, based on various technologies (e.g.mobile phone data exchanges, fixed cameras, GPS fleet tracking) arebeing used to identify traffic delays and to feed the information intonotification systems.

PNDs of this type may typically be mounted on the dashboard orwindscreen of a vehicle, but may also be formed as part of an on-boardcomputer of the vehicle radio or indeed as part of the control system ofthe vehicle itself. The navigation device may also be part of ahand-held system, such as a PDA (Portable Digital Assistant) a mediaplayer, a mobile phone or the like, and in these cases, the normalfunctionality of the hand-held system is extended by means of theinstallation of software on the device to perform both route calculationand navigation along a calculated route.

Route planning and navigation functionality may also be provided by adesktop or mobile computing resource running appropriate software. Forexample, the Royal Automobile Club (RAC) provides an on-line routeplanning and navigation facility at http://www.rac.co.uk, which facilityallows a user to enter a start point and a destination whereupon theserver to which the user's PC is connected calculates a route (aspectsof which may be user specified), generates a map, and generates a set ofexhaustive navigation instructions for guiding the user from theselected start point to the selected destination. The facility alsoprovides for pseudo three-dimensional rendering of a calculated route,and route preview functionality which simulates a user travelling alongthe route and thereby provides the user with a preview of the calculatedroute.

In the context of a PND, once a route has been calculated, the userinteracts with the navigation device to select the desired calculatedroute, optionally from a list of proposed routes. Optionally, the usermay intervene in, or guide the route selection process, for example byspecifying that certain routes, roads, locations or criteria are to beavoided or are mandatory for a particular journey. The route calculationaspect of the PND forms one primary function, and navigation along sucha route is another primary function.

During navigation along a calculated route, it is usual for such PNDs toprovide visual and/or audible instructions to guide the user along achosen route to the end of that route, i.e. the desired destination. Itis also usual for PNDs to display map information on-screen during thenavigation, such information regularly being updated on-screen so thatthe map information displayed is representative of the current locationof the device, and thus of the user or user's vehicle if the device isbeing used for in-vehicle navigation.

An icon displayed on-screen typically denotes the current devicelocation, and is centred with the map information of current andsurrounding roads in the vicinity of the current device location andother map features also being displayed. Additionally, navigationinformation may be displayed, optionally in a status bar above, below orto one side of the displayed map information, examples of navigationinformation include a distance to the next deviation from the currentroad required to be taken by the user, the nature of that deviationpossibly being represented by a further icon suggestive of theparticular type of deviation, for example a left or right turn. Thenavigation function also determines the content, duration and timing ofaudible instructions by means of which the user can be guided along theroute. As can be appreciated a simple instruction such as “turn left in100 m” requires significant processing and analysis. As previouslymentioned, user interaction with the device may be by a touch screen, oradditionally or alternately by steering column mounted remote control,by voice activation or by any other suitable method.

A further important function provided by the device is automatic routere-calculation in the event that: a user deviates from the previouslycalculated route during navigation (either by accident orintentionally); real-time traffic conditions dictate that an alternativeroute would be more expedient and the device is suitably enabled torecognize such conditions automatically, or if a user actively causesthe device to perform route re-calculation for any reason.

It is also known to allow a route to be calculated with user definedcriteria; for example, the user may prefer a scenic route to becalculated by the device, or may wish to avoid any roads on whichtraffic congestion is likely, expected or currently prevailing. Thedevice software would then calculate various routes and weigh morefavourably those that include along their route the highest number ofpoints of interest (known as POIs) tagged as being for example of scenicbeauty, or, using stored information indicative of prevailing trafficconditions on particular roads, order the calculated routes in terms ofa level of likely congestion or delay on account thereof. OtherPOI-based and traffic information-based route calculation and navigationcriteria are also possible.

Although the route calculation and navigation functions are fundamentalto the overall utility of PNDs, it is possible to use the device purelyfor information display, or “free-driving”, in which only mapinformation relevant to the current device location is displayed, and inwhich no route has been calculated and no navigation is currently beingperformed by the device. Such a mode of operation is often applicablewhen the user already knows the route along which it is desired totravel and does not require navigation assistance.

Devices of the type described above, for example the 720T modelmanufactured and supplied by TomTom International B.V., provide areliable means for enabling users to navigate from one position toanother.

A problem arises with respect to changes to road networks which occurtemporarily. For example, as a result of an event, such as a sporting orcultural event, or as a result of work being undertaken either to a roador proximal to it, changes to a road network occur, such as the closureof roads. However, such changes are not reflected in the map data uponwhich route planning, navigation and guidance is provided. This mayresult in a user of a navigation device being directed along closed orbusy roads.

It is an aim of the present invention to address this problem, inparticular to attempt to allow temporary changes to road networks to beaccounted for in route determination, navigation and guidance.

SUMMARY OF THE INVENTION

In pursuit of this aim, a presently preferred embodiment of the presentinvention provides a navigation device comprising a processor, and astore containing map data, wherein the map data comprises atemporally-variable feature, and the processor is arranged to determine,in a route planning process, a status of the temporally-variable featureaccording to temporal information.

The temporally-variable feature of the map data may be a map featurehaving a temporally-variable attribute or a map feature havingtemporally-variable validity. Preferably, the temporally-variableattribute has a value which is different for at least two times or timeperiods defined in the map data, or the temporally-variable validityindicates that the map feature forms can be considered in the routeplanning process for one or more periods of time defined in the mapdata.

The temporally-variable attribute may be speed or weighting information,used to determine a cost of a road segment in the route planningprocess, associated with the road segment. The temporally-variablevalidity may indicate one or more periods of time for which a mapfeature is available for consideration in the route planning process.

Information associated with the temporally-variable feature may indicatea period of time for which the feature is temporally-variable. Theperiod of time may be indicated by a start time, a duration and/or anend time, or as a function of time.

The map data may comprise first map data including map featureinformation and second map data comprising the temporally variablefeature. The first map data may not be temporally-variable. The secondmap data may have been received from an external source and stored inthe store subsequent to the first map data.

The navigation device may comprise a temporal mapping module arranged todetermine a status of the temporally-variable feature according to thetemporal information. The map data may comprise a plurality oftemporally-variable features, each feature having associated temporalinformation indicating a period of time for which the respective featureis temporally-variable.

Another embodiment of the present invention relates to a method ofdetermining a route from a start location to a destination location by aprocessor, comprising steps of: determining a status of one or moretemporally-variable map features according to temporal information, anddetermining the route from the start location to the destinationlocation with respect to the status of the one or moretemporally-variable map features. The processor may be a processor of anavigation device.

Yet another embodiment of the present invention relates to computersoftware comprising one or more software modules operable, when executedin an execution environment, to cause a processor to determining astatus of one or more temporally-variable map features according totemporal information, and determining the route from the start locationto the destination location with respect to the status of the one ormore temporally-variable map features. The processor may be a processorof a navigation device.

Advantages of these embodiments are set out hereafter, and furtherdetails and features of each of these embodiments are defined in theaccompanying dependent claims and elsewhere in the following detaileddescription.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of the teachings of the present invention, andarrangements embodying those teachings, will hereafter be described byway of illustrative example with reference to the accompanying drawings,in which:

FIG. 1 is a schematic illustration of a Global Positioning System (GPS);

FIG. 2 is a schematic illustration of electronic components arranged toprovide a navigation device;

FIG. 3 is a schematic illustration of the manner in which a navigationdevice may receive information over a wireless communication channel;

FIGS. 4A and 4B are illustrative perspective views of a navigationdevice;

FIG. 5 is a schematic representation of the software employed by thenavigation device;

FIGS. 6a and 6b is an illustration of an exemplary portion of map dataand an attribute of the map data which has a temporally-variable value;

FIGS. 7a and 7b is an illustration of map data including a featurehaving temporally-variable validity;

FIG. 8 illustrates a system for communicating temporally-variable mapdata;

FIG. 9 is map data illustrating a process of determining attributevalues; and

FIG. 10 is map data illustrating the assignment of attribute values toroads in a vicinity of an event.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will now be describedwith particular reference to a PND. It should be remembered, however,that the teachings of the present invention are not limited to PNDs butare instead universally applicable to any type of processing device thatis configured to execute navigation software so as to provide routeplanning and navigation functionality. It follows therefore that in thecontext of the present application, a navigation device is intended toinclude (without limitation) any type of route planning and navigationdevice, irrespective of whether that device is embodied as a PND, anavigation device built into a vehicle, or indeed a computing resource(such as a desktop or portable personal computer (PC), mobile telephoneor portable digital assistant (PDA)) executing route planning andnavigation software.

It will also be apparent from the following that the teachings of thepresent invention even have utility in circumstances where a user is notseeking instructions on how to navigate from one point to another, butmerely wishes to be provided with a view of a given location. In suchcircumstances the “destination” location selected by the user need nothave a corresponding start location from which the user wishes to startnavigating, and as a consequence references herein to the “destination”location or indeed to a “destination” view should not be interpreted tomean that the generation of a route is essential, that travelling to the“destination” must occur, or indeed that the presence of a destinationrequires the designation of a corresponding start location.

With the above provisos in mind, FIG. 1 illustrates an example view ofGlobal Positioning System (GPS), usable by navigation devices. Suchsystems are known and are used for a variety of purposes. In general,GPS is a satellite-radio based navigation system capable of determiningcontinuous position, velocity, time, and in some instances directioninformation for an unlimited number of users. Formerly known as NAVSTAR,the GPS incorporates a plurality of satellites which orbit the earth inextremely precise orbits. Based on these precise orbits, GPS satellitescan relay their location to any number of receiving units.

The GPS system is implemented when a device, specially equipped toreceive GPS data, begins scanning radio frequencies for GPS satellitesignals. Upon receiving a radio signal from a GPS satellite, the devicedetermines the precise location of that satellite via one of a pluralityof different conventional methods. The device will continue scanning, inmost instances, for signals until it has acquired at least threedifferent satellite signals (noting that position is not normally, butcan be determined, with only two signals using other triangulationtechniques). Implementing geometric triangulation, the receiver utilizesthe three known positions to determine its own two-dimensional positionrelative to the satellites. This can be done in a known manner.Additionally, acquiring a fourth satellite signal will allow thereceiving device to calculate its three dimensional position by the samegeometrical calculation in a known manner. The position and velocitydata can be updated in real time on a continuous basis by an unlimitednumber of users.

As shown in FIG. 1, the GPS system is denoted generally by referencenumeral 100. A plurality of satellites 120 are in orbit about the earth124. The orbit of each satellite 120 is not necessarily synchronous withthe orbits of other satellites 120 and, in fact, is likely asynchronous.A GPS receiver 140 is shown receiving spread spectrum GPS satellitesignals 160 from the various satellites 120.

The spread spectrum signals 160, continuously transmitted from eachsatellite 120, utilize a highly accurate frequency standard accomplishedwith an extremely accurate atomic clock. Each satellite 120, as part ofits data signal transmission 160, transmits a data stream indicative ofthat particular satellite 120. It is appreciated by those skilled in therelevant art that the GPS receiver device 140 generally acquires spreadspectrum GPS satellite signals 160 from at least three satellites 120for the GPS receiver device 140 to calculate its two-dimensionalposition by triangulation. Acquisition of an additional signal,resulting in signals 160 from a total of four satellites 120, permitsthe GPS receiver device 140 to calculate its three-dimensional positionin a known manner.

FIG. 2 is an illustrative representation of electronic components of anavigation device 200 according to a preferred embodiment of the presentinvention, in block component format. It should be noted that the blockdiagram of the navigation device 200 is not inclusive of all componentsof the navigation device, but is only representative of many examplecomponents.

The navigation device 200 is located within a housing (not shown). Thehousing includes a processor 210 connected to an input device 220 and adisplay screen 240. The input device 220 can include a keyboard device,voice input device, touch panel and/or any other known input deviceutilised to input information; and the display screen 240 can includeany type of display screen such as an LCD display, for example. In aparticularly preferred arrangement the input device 220 and displayscreen 240 are integrated into an integrated input and display device,including a touchpad or touchscreen input so that a user need only toucha portion of the display screen 240 to select one of a plurality ofdisplay choices or to activate one of a plurality of virtual buttons.

The navigation device may include an output device 260, for example anaudible output device (e.g. a loudspeaker). As output device 260 canproduce audible information for a user of the navigation device 200, itis should equally be understood that input device 240 can include amicrophone and software for receiving input voice commands as well.

In the navigation device 200, processor 210 is operatively connected toand set to receive input information from input device 220 via aconnection 225, and operatively connected to at least one of displayscreen 240 and output device 260, via output connections 245, to outputinformation thereto. Further, the processor 210 is operably coupled to amemory resource 230 via connection 235 and is further adapted toreceive/send information from/to input/output (I/O) ports 270 viaconnection 275, wherein the I/O port 270 is connectible to an I/O device280 external to the navigation device 200. The memory resource 230comprises, for example, a volatile memory, such as a Random AccessMemory (RAM) and a non-volatile memory, for example a digital memory,such as a flash memory. The external I/O device 280 may include, but isnot limited to an external listening device such as an earpiece forexample. The connection to I/O device 280 can further be a wired orwireless connection to any other external device such as a car stereounit for hands-free operation and/or for voice activated operation forexample, for connection to an ear piece or head phones, and/or forconnection to a mobile phone for example, wherein the mobile phoneconnection may be used to establish a data connection between thenavigation device 200 and the internet or any other network for example,and/or to establish a connection to a server via the internet or someother network for example.

FIG. 2 further illustrates an operative connection between the processor210 and an antenna/receiver 250 via connection 255, wherein theantenna/receiver 250 can be a GPS antenna/receiver for example. It willbe understood that the antenna and receiver designated by referencenumeral 250 are combined schematically for illustration, but that theantenna and receiver may be separately located components, and that theantenna may be a GPS patch antenna or helical antenna for example.

Further, it will be understood by one of ordinary skill in the art thatthe electronic components shown in FIG. 2 are powered by power sources(not shown) in a conventional manner. As will be understood by one ofordinary skill in the art, different configurations of the componentsshown in FIG. 2 are considered to be within the scope of the presentapplication. For example, the components shown in FIG. 2 may be incommunication with one another via wired and/or wireless connections andthe like. Thus, the scope of the navigation device 200 of the presentapplication includes a portable or handheld navigation device 200.

In addition, the portable or handheld navigation device 200 of FIG. 2can be connected or “docked” in a known manner to a vehicle such as abicycle, a motorbike, a car or a boat for example. Such a navigationdevice 200 is then removable from the docked location for portable orhandheld navigation use.

Referring now to FIG. 3, the navigation device 200 may establish a“mobile” or telecommunications network connection with a server 302 viaa mobile device (not shown) (such as a mobile phone, PDA, and/or anydevice with mobile phone technology) establishing a digital connection(such as a digital connection via known Bluetooth technology forexample). Thereafter, through its network service provider, the mobiledevice can establish a network connection (through the internet forexample) with a server 302. As such, a “mobile” network connection isestablished between the navigation device 200 (which can be, and oftentimes is mobile as it travels alone and/or in a vehicle) and the server302 to provide a “real-time” or at least very “up to date” gateway forinformation.

The establishing of the network connection between the mobile device(via a service provider) and another device such as the server 302,using an internet (such as the World Wide Web) for example, can be donein a known manner. This can include use of TCP/IP layered protocol forexample. The mobile device can utilize any number of communicationstandards such as CDMA, GSM, WAN, etc.

As such, an internet connection may be utilised which is achieved viadata connection, via a mobile phone or mobile phone technology withinthe navigation device 200 for example. For this connection, an internetconnection between the server 302 and the navigation device 200 isestablished. This can be done, for example, through a mobile phone orother mobile device and a GPRS (General Packet Radio Service)-connection(GPRS connection is a high-speed data connection for mobile devicesprovided by telecom operators; GPRS is a method to connect to theinternet).

The navigation device 200 can further complete a data connection withthe mobile device, and eventually with the internet and server 302, viaexisting Bluetooth technology for example, in a known manner, whereinthe data protocol can utilize any number of standards, such as the GSRM,the Data Protocol Standard for the GSM standard, for example.

The navigation device 200 may include its own mobile phone technologywithin the navigation device 200 itself (including an antenna forexample, or optionally using the internal antenna of the navigationdevice 200). The mobile phone technology within the navigation device200 can include internal components as specified above, and/or caninclude an insertable card (e.g. Subscriber Identity Module or SIMcard), complete with necessary mobile phone technology and/or an antennafor example. As such, mobile phone technology within the navigationdevice 200 can similarly establish a network connection between thenavigation device 200 and the server 302, via the internet for example,in a manner similar to that of any mobile device.

For GRPS phone settings, a Bluetooth enabled navigation device may beused to correctly work with the ever changing spectrum of mobile phonemodels, manufacturers, etc., model/manufacturer specific settings may bestored on the navigation device 200 for example. The data stored forthis information can be updated.

In FIG. 3 the navigation device 200 is depicted as being incommunication with the server 302 via a generic communications channel318 that can be implemented by any of a number of differentarrangements. The server 302 and a navigation device 200 can communicatewhen a connection via communications channel 318 is established betweenthe server 302 and the navigation device 200 (noting that such aconnection can be a data connection via mobile device, a directconnection via personal computer via the internet, etc.).

The server 302 includes, in addition to other components which may notbe illustrated, a processor 304 operatively connected to a memory 306and further operatively connected, via a wired or wireless connection314, to a mass data storage device 312. The processor 304 is furtheroperatively connected to transmitter 308 and receiver 310, to transmitand send information to and from navigation device 200 viacommunications channel 318. The signals sent and received may includedata, communication, and/or other propagated signals. The transmitter308 and receiver 310 may be selected or designed according to thecommunications requirement and communication technology used in thecommunication design for the navigation system 200. Further, it shouldbe noted that the functions of transmitter 308 and receiver 310 may becombined into a signal transceiver.

Server 302 is further connected to (or includes) a mass storage device312, noting that the mass storage device 312 may be coupled to theserver 302 via communication link 314. The mass storage device 312contains a store of navigation data and map information, and can againbe a separate device from the server 302 or can be incorporated into theserver 302.

The navigation device 200 is adapted to communicate with the server 302through communications channel 318, and includes processor, memory, etc.as previously described with regard to FIG. 2, as well as transmitter320 and receiver 322 to send and receive signals and/or data through thecommunications channel 318, noting that these devices can further beused to communicate with devices other than server 302. Further, thetransmitter 320 and receiver 322 are selected or designed according tocommunication requirements and communication technology used in thecommunication design for the navigation device 200 and the functions ofthe transmitter 320 and receiver 322 may be combined into a singletransceiver.

Software stored in server memory 306 provides instructions for theprocessor 304 and allows the server 302 to provide services to thenavigation device 200. One service provided by the server 302 involvesprocessing requests from the navigation device 200 and transmittingnavigation data from the mass data storage 312 to the navigation device200. Another service provided by the server 302 includes processing thenavigation data using various algorithms for a desired application andsending the results of these calculations to the navigation device 200.

The communication channel 318 generically represents the propagatingmedium or path that connects the navigation device 200 and the server302. Both the server 302 and navigation device 200 include a transmitterfor transmitting data through the communication channel and a receiverfor receiving data that has been transmitted through the communicationchannel.

The communication channel 318 is not limited to a particularcommunication technology. Additionally, the communication channel 318 isnot limited to a single communication technology; that is, the channel318 may include several communication links that use a variety oftechnology. For example, the communication channel 318 can be adapted toprovide a path for electrical, optical, and/or electromagneticcommunications, etc. As such, the communication channel 318 includes,but is not limited to, one or a combination of the following: electriccircuits, electrical conductors such as wires and coaxial cables, fibreoptic cables, converters, radio-frequency (RF) waves, the atmosphere,empty space, etc. Furthermore, the communication channel 318 can includeintermediate devices such as routers, repeaters, buffers, transmitters,and receivers, for example.

In one illustrative arrangement, the communication channel 318 includestelephone and computer networks. Furthermore, the communication channel318 may be capable of accommodating wireless communication such as radiofrequency, microwave frequency, infrared communication, etc.Additionally, the communication channel 318 can accommodate satellitecommunication.

The communication signals transmitted through the communication channel318 include, but are not limited to, signals as may be required ordesired for given communication technology. For example, the signals maybe adapted to be used in cellular communication technology such as TimeDivision Multiple Access (TDMA), Frequency Division Multiple Access(FDMA), Code Division Multiple Access (CDMA), Global System for MobileCommunications (GSM), etc. Both digital and analogue signals can betransmitted through the communication channel 318. These signals may bemodulated, encrypted and/or compressed signals as may be desirable forthe communication technology.

The server 302 includes a remote server accessible by the navigationdevice 200 via a wireless channel. The server 302 may include a networkserver located on a local area network (LAN), wide area network (WAN),virtual private network (VPN), etc.

The server 302 may include a personal computer such as a desktop orlaptop computer, and the communication channel 318 may be a cableconnected between the personal computer and the navigation device 200.Alternatively, a personal computer may be connected between thenavigation device 200 and the server 302 to establish an internetconnection between the server 302 and the navigation device 200.Alternatively, a mobile telephone or other handheld device may establisha wireless connection to the internet, for connecting the navigationdevice 200 to the server 302 via the internet.

The navigation device 200 may be provided with information from theserver 302 via information downloads which may be periodically updatedautomatically or upon a user connecting navigation device 200 to theserver 302 and/or may be more dynamic upon a more constant or frequentconnection being made between the server 302 and navigation device 200via a wireless mobile connection device and TCP/IP connection forexample. For many dynamic calculations, the processor 304 in the server302 may be used to handle the bulk of the processing needs, however,processor 210 of navigation device 200 can also handle much processingand calculation, oftentimes independent of a connection to a server 302.

As indicated above in FIG. 2, a navigation device 200 includes aprocessor 210, an input device 220, and a display screen 240. The inputdevice 220 and display screen 240 are integrated into an integratedinput and display device to enable both input of information (via directinput, menu selection, etc.) and display of information through a touchpanel screen, for example. Such a screen may be a touch input LCDscreen, for example, as is well known to those of ordinary skill in theart. Further, the navigation device 200 can also include any additionalinput device 220 and/or any additional output device 241, such as audioinput/output devices for example.

FIGS. 4A and 4B are perspective views of a navigation device 200. Asshown in FIG. 4A, the navigation device 200 may be a unit that includesan integrated input and display device 290 (a touch panel screen forexample) and the other components of FIG. 2 (including but not limitedto internal GPS receiver 250, microprocessor 210, a power supply, memorysystems 230, etc.).

The navigation device 200 may sit on an arm 292, which itself may besecured to a vehicle dashboard/window/etc. using a suction cup 294. Thisarm 292 is one example of a docking station to which the navigationdevice 200 can be docked.

As shown in FIG. 4B, the navigation device 200 can be docked orotherwise connected to an arm 292 of the docking station by snapconnecting the navigation device 292 to the arm 292 for example. Thenavigation device 200 may then be rotatable on the arm 292, as shown bythe arrow of FIG. 4B. To release the connection between the navigationdevice 200 and the docking station, a button on the navigation device200 may be pressed, for example. Other equally suitable arrangements forcoupling and decoupling the navigation device to a docking station arewell known to persons of ordinary skill in the art.

Referring now to FIG. 5 of the accompanying drawings, the memoryresource 230 stores a boot loader program (not shown) that is executedby the processor 210 in order to load an operating system 470 from thememory resource 230 for execution by functional hardware components 460,which provides an environment in which application software 480 can run.The operating system 470 serves to control the functional hardwarecomponents 460 and resides between the application software 480 and thefunctional hardware components 460. The application software 480provides an operational environment including the GUI that supports corefunctions of the navigation device 200, for example map viewing, routeplanning, navigation functions and any other functions associatedtherewith. In accordance with the preferred embodiment of the presentinvention, part of this functionality comprises a temporal mappingmodule 490, the function of which will now be described in detail inconnection with the following figures.

Embodiments of the present invention concern temporally-variable mapdata. Temporally-variable map data is data which includes informationabout map features, such as about locations and/or roads. At least oneaspect of the temporally-variable map data is time-dependant. That is,at least one part of the map data changes with time i.e. changes duringone or more periods of time defined in the temporally-variable map data.Changes may be an addition or deletion of a feature in the map data, ora change in an attribute of the map data. For example, thetemporally-variable map data may include feature information identifyinga map feature, such as a road, which is only valid, i.e. forms part ofthe map data, for a specified period of time. Examples of featureshaving temporally-variable validity are temporary roads or car parkswhich are established or opened for an event. In these cases, an accessroad or car park may be opened for a period of time specified in advancee.g. between two particular dates/times. In this way,temporally-variable map data differs from traffic information, which mayindicate that a road is closed and be taken into account in a routeplanning process, since the closure due to traffic conditions would notbe known in advance. In contrast, temporally-variable map data includespredetermined temporal information i.e. is known in advance, for exampleat a time of storing the map data.

Examples of temporally-variable map data are: the addition of a mapfeature, such as one or more of a road, point of interest (POI), carpark, etc; the closure or restriction of a map feature, such as one ormore of a road, POI, car park, etc.; or a change of one or moreattributes in the map data, such as an speed or weight informationassociated with one or more road segments. Furthermore, temporarydiversions may be included in the temporally-variant map data whichredirect destination locations to other locations such that then thedestination location is selected in a route planning process anothersubstitute destination is used for the destination.

Temporally-variable map data may include temporal information in anumber of ways. In one embodiment, the temporally-variable map dataincludes a start time indicating a time at which a change in the mapdata begins and a duration for which the change is operative. In anotherembodiment, the temporally-variable map data includes a start timeindicating a time at which a change in the map data begins and an endtime indicating a time at which the change to the map data ends i.e. thechange is reversed. In another embodiment, the temporally-variable mapdata includes the start time, the end time and a plurality ofintermediate time periods at which an attribute assumes different i.e.intermediate values.

The temporally-variable map data may be stored within and utilised bythe navigation device 200 during a route planning process. During theroute planning process the map data is considered in relation to a timefor which a journey is being planned in order to determine a route. Thatis, if the route is being planned for a time at which a temporal changehas been made to the map data, the change is considered during the routeplanning process. In some embodiments, as will be explained, thetemporally-variable map data is used to modify existing map data. Thatis, the temporally-variable map data acts as a “patch” to modifyexisting map data such that temporally-variable map data changes theexisting map data for one or more periods of time indicated in thetemporally-variable map data. The temporally variable map data may becommunicated to navigation devices 200 via the communications channel318.

Temporally-variable map data will now be explained in more detail withreference to FIGS. 6 to 10.

Referring a portion of map data is illustrated in FIG. 6(a) whichcontains four locations A-D, shown as nodes, and four roads 601-604linking those locations, shown as edges. FIG. 6(b) illustrates atemporally-variable expected average speed for road 602 which linkslocations B and D. The expected average speed is an attribute of road602 which is considered in a route planning process involving the road602. However, other speeds, such as maximum speed, may be considered.The expected average speed for road 602 is a predetermined value s₁until a first predetermined time t₁. The expected average speed drops to0 between times t₁ and a second predetermined time t₂, whereupon itreturns to the previous expected average speed s₁. The reduction in theaverage speed for road 602 to 0 between times t₁ and t₂ effectivelycauses road 602 to be discarded from consideration during the routeplanning process between times t₁ and t₂. In other words, road 602 isconsidered to be closed between times t₁ and t₂. For example, this maybe due to expected maintenance work taking place on the road 602 or anevent, such as a carnival, taking place proximal to the road 602 betweentimes t₁ and t₂ Whilst in the temporally-variable map data shown in FIG.6(a), the expected average speed of road 602 is reduced to 0 to indicateclosure of the road between times t₁ and t₂, the same effect may beachieved in different ways, for example by changing value of a maximumspeed attribute of road 602 between times t₁ and t₂ considered in theroute planning process. Furthermore, whilst the expected average speedfor road 602 is reduced to 0, one or more other predetermined expectedaverage speeds may be considered. For example, the expected averagespeed may be reduced to a non-zero value s₂ between t₁ and apredetermined time t₃ intermediate to times t₁ and t₂, and 0 between t₃and t₂. It will be noted that these are merely illustrative values andtimes. Temporally-variable map data may also include an attribute thevalue of which varies as a function of time or algorithmically. Forexample, the average speed for a road in the map data is defined tochange as a function of time. Similarly, a weight of a road in the mapdata may change as a function of time i.e. the average speed changesaccording to f(t).

Continuing to refer to the example temporally-variable map data shown inFIG. 6(b), at a time between t₀ and t₁, a user utilising a navigationdevice 200 having stored therein the map data illustrated in FIG. 6operates the navigation device 200 to determine a route from a startlocation A to a destination location D. According to user preferenceinformation stored in the navigation device 200, the determined route isto be the fastest route from A to D, although it may be realised thatthe user preferences may indicate that other routes are desired e.g. theshortest route, route excluding certain types of road etc. The routedetermined by the navigation device comprises roads 601 and 602. Road602 is included in the determined route in preference to roads 603 and604, which could also be used to reach location D from intermediatelocation B, via location C, due to it being faster (according to theuser's preference) to reach location D from location B than using roads603 and 604. In other words, the road 602 has a combination or greaterexpected average speed and/or shorter distance than roads 602 and 604which is set as the user's preference for route determination. However,between times t₁ and t₂ when the same route between locations A and D isdetermined by the navigation device 200 according to the same userpreferences, the determined route includes roads 601, 603 and 604 due tothe road 602 having an expected average speed of 0. In this way, thetemporally-variable map data implements a temporary closure orrestriction of a feature in the map data, which is known in advance incontrast to utilisation of dynamically received traffic information.

In another example of temporally-variable map data, a weight or costattribute associated with one or more vertices in the map data istemporally variable. For example, the weight or cost attribute of road602 shown in FIG. 6(a) may be changed between times t₁ and t₂ to a valuedifferent to that prior to time t₁ and subsequent to time t₂. Weights orcost attributes may be considered in a route planning process which aimsto find a minimised weight or cost for a determined route by consideringa sum of weights or costs of possible routes between a start locationand a destination location. For example, the route planning process maybe based upon Dijkstra's algorithm or a variation thereof. The weight orcost attribute of each road segment may correspond to a length of theroad segment, wherein a shortest route may be found by determining theroute between the start and destination locations having the lowestweight or cost. Alternatively, the weight or cost may be based upon acombination of the length of road segment and an expected average ormaximum speed of that road segment. In this case, determining the routebetween the start and destination locations having the lowest weight orcost finds the fastest route between the start and destinationlocations. In one embodiment of the temporally variable map data, aweight or cost attribute of a road segment is increased in order toreduce a likelihood of that road segment being included in a determinedroute. For example, between times t₁ and t₂ the weight or cost attributeof road 602 may be increased to a predetermined value greater than theweight or cost value of road 602 outside those times. The predeterminedweight may be infinite, which would effectively render the road segmentclosed, although a predetermined value may be chosen which is muchhigher than would be expected of realistic road segments.

FIGS. 7(a) and (b) illustrates a further example of temporally-variablemap data. In the example described a feature is temporarily introducedinto the map data. In the illustrated example, a temporary diversion isincluded in the map data for a period of time. The diversion isestablished between a POI, for example an event location, and a carparking area. However, it will be realised that other temporallyvariable features may be included in the map data. The illustratedportion of map data shown in FIG. 7(a) includes five locations E-I,shown as nodes, and six roads 701-706, which are represented as edges,linking those locations. A POI 707 is included in the illustratedportion of map data. The POI may be one of an event location e.g.showground, sports stadium or the like where it is expected that a largenumber of visitors will attend during a predetermined time period of anevent. In order to cope with the expected number of visitors, theauthorities have provided a car park 709.

The car park may or may be permanent or temporary i.e. provided solelyfor the duration of the event. However, as indicated by FIG. 7(b) duringthe event visitors are to be directed to the car park 709, rather thanto the POI 707 itself by inclusion of a temporary diversion 708 in themap data between the POI 707 and the car park 709. A user of anavigation device selecting the POI 707 as a destination location duringthe duration of the event is automatically directed to the car park 709i.e. the car park 709 is set as the destination in place of the POI 707.This may be achieved by storing as an attribute of the POI, redirectioninformation which automatically sets the destination location to that ofthe car park 709 by following diversion 708. Furthermore, in order todeter visitors from utilising roads 704, 709, an attribute of theseroads, such as their respective expected average or maximum speedattributes, or their weights may be altered during the duration of theevent. For example, a user setting location F as a start location andPOI as the destination outside of the event duration would be directedvia a route including roads 703 and 705. However, during the duration ofthe event, the destination location would automatically be changed tothe car park 709 and the determined route include roads 701, 702 and apart of road 706 to the car park 709 due to the reduction in expectedaverage speeds of roads 704 and 705 causing the determined route to govia roads 701 and 702 in preference.

FIG. 8 illustrates a system in which temporally-variant map data iscommunicated to a navigation device. The system 800 comprises anavigation device 810 which has map data 815 stored therein, for examplein memory 230. FIG. 8 provides an illustration of the map data 815comprising locations A-D and roads 801-804 connecting those locations.The map data 815 further comprises expected average speed informationfor each road in the map data 815, which is used in a route planningprocess. It will be realised that the map data 815 may comprise otherinformation, such as weight information for each road, which enables acost of a route to be determined according to one or more criteria. Thenavigation device 810 is communicatively coupled to a server 820 via adata communications channel 830 which may be direct or indirect i.e. viaanother device such as a mobile telephone, or include data stored on aremovable storage medium, such as a memory card. The server 820 isarranged to transmit temporally-variant map data 840 to the navigationdevice 840 via the communications channel 830. In order to avoid a needto communicate the entire map data 815 containing temporally-variantinformation to the navigation device 810, the temporally-variant mapdata 840 is to be used in conjunction with the map data 815 stored inthe navigation device 810 by the temporal mapping module 490. As shownin FIG. 8, the temporally-variant map data 840 contains start timeinformation 841 identifying a start time of each change to the map data815, end time information 842 identifying an end time of each change tothe map data 815, feature information 843 identifying which feature ofthe map data 815 is to be changed, attribute information 844 identifyingan attribute of the feature to be changed e.g. expected average speed,maximum speed, weight, etc, and a changed value 845 for the attribute.Once the temporally variant map data 840 is received by the navigationdevice 810 and stored in the memory 230, the temporal mapping moduleutilises the temporally-variant map data 840 in conjunction with theexisting map data 815 such that attributes of the map data, i.e. averagespeed information of road 802, have the changed value 844 for a durationof time specified by the start and end information 841, 842 specified inthe temporally-variant map data 844 rather than the normal valuespecified by the map data 815.

FIG. 9(a) illustrates example map data comprising nine locations andtwelve roads linking those locations. As noted above, the map dataillustrated in FIG. 9(a) may be stored in a memory 230 of a navigationdevice 200. FIG. 9(b) illustrates a process of determiningtemporally-variant weights for roads in map data. The map data shown inFIG. 9(b) corresponds to that shown in FIG. 9(a). In addition, the mapdata shown in FIG. 9(b) includes a location of an event 913 and atemporary road 914 providing access to the event 913. In one embodimentof the invention, temporally-variant weightings for roads in a vicinityof the event are determined based upon a distance of each road from theevent 913. In the illustrated example, three levels oftemporally-variant weighting are applied to roads surround the event913. FIG. 9(b) shows three perimeters 920, 930, 940 plotted around theevent 913 at predetermined radii there-from. The three radii may befirst, second and third multiples of the same radius, or may bepredetermined value. For example, the first, second and third radii maybe 5, 10 and 15 km. However, in another embodiment, the first second andthird radii may be 5, 7 and 13 km. It will be realised that otherdistances may be selected as appropriate. Alternatively, weights may bedetermined as a continuous function based upon a distance from a mapfeature, such as the event 913. Roads 901, 903, 904, 913 which are atleast partly within the first perimeter 920 are assigned a first weightvalue; roads 902, 905, 906 at least partly within the second perimeter930 are assigned a second weight value; and roads 908, 909, 910 at leastpartly within the third perimeter 940 are assigned a third weight value.The assigned weight values may be determined based upon an initialweight value of each road, for example, by having a weight penalty addedto the initial weight of the road. Alternatively, the assigned weightvalues may be determined according to the perimeter in which each roadis partly located without reference to the initial weight value of theroad. For example, roads 901, 903, 904, 913 are assigned atemporally-variant weight value greater than roads 902, 905, 906 whichare assigned a temporally-variant weight value greater than roads 908,909. The assignment of graduated weights to roads according to theirdistance from the event 913 gradually discourages the inclusion of thoseroads into routes, unless it is necessary for those roads to be used toarrive at a destination location, such as event 913. For example, whenthe navigation device 200 is executing a route determination process todetermine a route from a start location to a destination location whichwould normally partly be proximal to the event 913, such as part of theroute running generally past the event on road 903, when considering thetemporally-variable map data in which the road 903 has been given arelatively high associated weight due to being within the firstperimeter 920, the route planning process may then determine a routeavoiding use of the road 903 due to its high cost. The same route duringthe event may include roads 905, 902 or other roads having an even lowerassociated cost. In this way, the assignment of weights to roadscorrespondingly closer to the event 913 has the effect of reducingpassing traffic in the locality of the event 913.

Whilst in the description associated with FIG. 9 it has been describedthat roads at least partly entering a perimeter are assigned acorresponding weight value, in another embodiment, road segments may besubdivided such that a temporally-variant weight is only assigned to apart of a road located within each perimeter 920, 930, 940. For example,a portion of road 906 located internal to second perimeter 930 isassigned the second weight value, whereas the portion of the road 906outside the second perimeter 930 but inside the third perimeter 940 isassigned the third weight value. The weight value of the portion of road906 outside the third perimeter 940 is not changed. As describedpreviously with reference to FIG. 8, temporally variant map data 840 iscommunicated to the navigation device 810 for use in combination withthe existing map data 815 stored therein.

FIG. 10 illustrates a use of temporally-variant map data to encouragevehicles to use predetermined roads in preference to other roads. Mapdata is shown in FIG. 10 comprising nine locations and twelve roads1001-1011 linking those locations. A POI 1013, which could also beconsidered as a tenth location, such as an event is also included in themap data. Roads 1001, 1002, 1004, 1005, 1007, 1009 and 1012 have arelatively high vehicle capacity i.e. are capable of carrying morevehicles per hour than roads 1003, 1006, 1008, 1011. To denote thehigher capacity, roads 1001, 1002, 1004, 1005, 1007, 1009 and 1012 inFIG. 10 are shown in bold. Of course, it may also be desired for roads1001, 1002, 1004, 1005, 1007, 1009 and 1012 to carry more traffic forother reasons, such as air/noise pollution, not including certainfeatures such as traffic calming, bridges etc, being more easilyaccessible for emergency vehicles etc. A user at start locationindicated in FIG. 10 sets the POI as a destination location. Undernormal circumstances when setting the destination location to be thelocation of the POI 1012, a determined route includes roads 1001, 1002,1003, 1008. The route may be determined according to a variant ofDijkstra's algorithm by determining a lowest-weight route between thestart location and the POI 1013. However, the route includes roads 1003,1008 which are of a relatively low vehicle capacity. In order toencourage vehicles to avoid the lower capacity roads, i.e. roads 1003,1008, for the duration of the event, i.e. between first and secondpredetermined times, temporal map data 840 contains attributeinformation which reduces a weight of the high capacity roads 1001,1002, 1004, 1005, 1007, 1009 and 1012 relative to lower capacity roads1003, 1006, 1008, 1011. At a time between the first and second times, anavigation device 810 operated to determine a route between the startlocation and the POI 1013 determines a route to include roads 1001,1002, 1005, 1009, 1010. The lower weighting of roads 1005, 1009, 1010 incomparison to roads 1003, 1008 causes the temporal mapping module 490 tocombine the temporally variable map data with the existing map dataaccessible to the navigation device and select roads 1005, 1009, 1010 ashaving a combined lower weight than roads 1003, 1008. Thus, vehiclesfollowing the route determined y the navigation device during the eventare directed to the POI 1013 along higher capacity roads. However priorand subsequent to the event the weight of roads surrounding the POI 1013is returned to normal such that roads 1003, 1008, 1006, 1011 are morelikely to be included in the determined routes.

It will be apparent from the foregoing that the teachings of the presentinvention provide an arrangement whereby predeterminedtemporally-variant map data may be used by a navigation device totemporarily affect route determination. Temporally-variant map data isuseful to affect vehicular traffic during temporary events.

It will also be appreciated that whilst various aspects and embodimentsof the present invention have heretofore been described, the scope ofthe present invention is not limited to the particular arrangements setout herein and instead extends to encompass all arrangements, andmodifications and alterations thereto, which fall within the scope ofthe appended claims.

For example, whilst embodiments described in the foregoing detaileddescription refer to GPS, it should be noted that the navigation devicemay utilise any kind of position sensing technology as an alternative to(or indeed in addition to) GPS. For example the navigation device mayutilise using other global navigation satellite systems such as theEuropean Galileo system. Equally, it is not limited to satellite basedbut could readily function using ground based beacons or any other kindof system that enables the device to determine its geographic location.

It will also be well understood by persons of ordinary skill in the artthat whilst the preferred embodiment implements certain functionality bymeans of software, that functionality could equally be implementedsolely in hardware (for example by means of one or more ASICs(application specific integrated circuit)) or indeed by a mix ofhardware and software. As such, the scope of the present inventionshould not be interpreted as being limited only to being implemented insoftware.

Lastly, it should also be noted that whilst the accompanying claims setout particular combinations of features described herein, the scope ofthe present invention is not limited to the particular combinationshereafter claimed, but instead extends to encompass any combination offeatures or embodiments herein disclosed irrespective of whether or notthat particular combination has been specifically enumerated in theaccompanying claims at this time.

1-15. (canceled)
 16. A navigation device, comprising: a processor; and amemory store containing map data, the map data comprising one or moretemporally-variant features and predetermined temporal information foreach of the one or more temporally-variant features, wherein saidpredetermined temporal information includes: (i) a start time and an endtime; or (ii) a start time and duration, the processor being arrangedto: determine a route from a start location to a destination location ina route planning process, wherein said determining comprises:determining a status of at least one of the temporally-variant featuresaccording to the predetermined temporal information fortemporally-variant feature; determining a temporally-variant weightingfor each road in a vicinity of the at least one temporally-variantfeature based upon a distance of each road from the at least onetemporally-variant feature; and determining the route with respect tothe status of the at least one temporally-variant feature using thedetermined temporally-variant weightings; and provide the routedetermined in the route-planning process.
 17. The navigation device ofclaim 16, wherein the temporally-variant weighting is determined basedon whether a subdivided portion of each road in the vicinity of thetemporally-variable feature falls within one of a plurality of radiiemanating from the temporally-variable feature.
 18. The navigationdevice of claim 16, wherein the temporally-variant weighting isdetermined based on a continuous weighting function applied to thedistance of each road from the temporally-variant feature.
 19. Thenavigation device of claim 16, wherein the temporally-variant feature ofthe map data is a map feature having a temporally-variable attribute ora map feature having temporally-variable validity.
 20. The navigationdevice of claim 16, wherein the map data comprises first map datacomprising map feature information and second map data comprising thetemporally variable feature.
 21. The navigation device of claim 20,further comprising a data receiving device to receive data, wherein thesecond map data is received from the data receiving device and stored inthe store.
 22. The navigation device of claim 16, wherein thetemporally-variant feature is one or more of: a road; a point ofinterest (POI); and a car park.
 23. A method of determining a route froma start location to a destination location in a route-planning process,comprising: accessing, by a processor, a memory store containing mapdata, the map data comprising one or more temporally-variant featuresand predetermined temporal information for each of the one or moretemporally-variant features, wherein said predetermined temporalinformation includes: (i) a start time and an end time; or (ii) a starttime and duration; determining, by the processor, a status of at leastone of the temporally-variant features according to the predeterminedtemporal information for temporally-variant feature; determining, by theprocessor, a temporally-variant weighting for each road in a vicinity ofthe at least one temporally-variant feature based upon a distance ofeach road from the at least one temporally-variant feature; determining,by the processor, the route with respect to the status of the at leastone temporally-variant feature using the determined temporally-variantweightings; and providing, by the processor, the route determined in theroute-planning process.
 24. The method of claim 23, wherein thetemporally-variant weighting is determined based on whether a subdividedportion of each road in the vicinity of the temporally-variable featurefalls within one of a plurality of radii emanating from thetemporally-variable feature.
 25. The method of claim 23, wherein thetemporally-variant weighting is determined based on a continuousweighting function applied to the distance of each road from thetemporally-variant feature.
 26. The method of claim 23, wherein thetemporally-variant feature of the map data is a map feature having atemporally-variable attribute or a map feature havingtemporally-variable validity.
 27. The method of claim 23, wherein themap data comprises first map data comprising map feature information andsecond map data comprising the temporally variable feature.
 28. Themethod of claim 23, further receiving the second map data and storingthe received data in the store.
 29. The method of claim 23, wherein thetemporally-variant feature is one or more of: a road; a point ofinterest (POI); and a car park.
 30. A non-transitory computer-readablemedium which stores a set of instructions which, when executed by aprocessor, causes the processor to perform a method of determining aroute from a start location to a destination location in aroute-planning process, the method executed by the set of instructionscomprising: accessing a memory store containing map data, the map datacomprising one or more temporally-variant features and predeterminedtemporal information for each of the one or more temporally-variantfeatures, wherein said predetermined temporal information includes: (i)a start time and an end time; or (ii) a start time and duration;determining a status of at least one of the temporally-variant featuresaccording to the predetermined temporal information fortemporally-variant feature; determining a temporally-variant weightingfor each road in a vicinity of the at least one temporally-variantfeature based upon a distance of each road from the at least onetemporally-variant feature; determining the route with respect to thestatus of the at least one temporally-variant feature using thedetermined temporally-variant weightings; and providing the routedetermined in the route-planning process.
 31. The computer-readablemedium of claim 30, wherein the temporally-variant weighting isdetermined based on whether a subdivided portion of each road in thevicinity of the temporally-variable feature falls within one of aplurality of radii emanating from the temporally-variable feature. 32.The computer-readable medium of claim 30, wherein the temporally-variantweighting is determined based on a continuous weighting function appliedto the distance of each road from the temporally-variant feature.